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The blights that affect tomatoes (Solanum lycopersicum) can not only spoil individual tomato fruits, but -- in severe cases -- wipe out entire crops. Early blight is more common in eastern parts of the United States, but it's worth checking troubled plants for the telltale bull's-eye pattern on older leaves no matter where you live. Late blight often appears in any geographic area experiencing unusually cool, rainy periods. Late blight may show first as dark spots with powdery white margins, followed by massive foliage loss and dark spots on the tomatoes themselves. Buying blight-resistant plants and rotating crops is a key component of fighting blight, but treating the soil itself can also halt the spread of the disease.

1

Remove all vegetation from the tomato garden bed and other suspected garden areas at the end of the growing season after you detect blight in tomatoes, potatoes or other nightshade plants. Dig into the soil to uproot the entire plant, and pick up pieces of broken stems, fallen tomatoes and other plant parts.

2

Place vegetation in plastic bags, seal them and throw them away immediately.

3

Deeply till the garden bed in late fall. Disrupting the soil prevents blight spores from having an undisturbed place to spend the winter.

4

Examine the entire garden in the spring before treating or planting the soil. Remove any additional vegetation that may harbor blight. Look for volunteer tomato plants that may have sprouted nearby, as well as other members of the nightshade family, such as remaining potato vines and tubers, pepper or eggplant vegetation, and the weed known as nightshade.

5

Place vegetation in plastic bags, seal them and throw them away immediately.

6

Spread 4-inch layers each of sand and compost over the soil, and work the layers into the top 6 to 9 inches of the existing garden bed. This step will not only improve drainage, but will help the soil warm up faster by raising the garden bed slightly higher than the surrounding soil. Higher, drier growing conditions are less hospitable to fungal spores.

7

Cover garden beds with white plastic mulch, which heats the soil, reducing humidity and killing blight spores still lingering in the garden.

8

Cover pathways with mulch such as wood chips. If you are not using white plastic on garden beds, mulch these areas as well. The mulch cuts down on the chances of blight reaching the plants through splashing mud.

Things You Will Need

Spade

Plastic garbage bags and ties

Sand

Compost

White plastic mulch

Natural mulch (e.g., straw or wood chips)

Tips

Check with your local university extension service, county agent or a trusted area nursery to determine if certain diseases, including blight diseases, are common in your area. Tomato seed and seedling packets usually contain information about which problems the tomatoes have been bred to resist.

Rotate tomatoes and related plants each year. Remember that tomatoes, potatoes, peppers and eggplants all belong to the nightshade family, so it's never a good idea to follow a pepper crop, for example, with potatoes or tomatoes. Plant any of these plants where a different family of plants, such as cereal crops or legumes.

Warning

Fungicides applied directly to plants sometimes help control tomato blight. Keep in mind, however, that they are best used as a preventative, not as a cure. Copper fungicide, maneb and chlorothalonil are examples of sprays sometimes applied for tomato blight prevention.